Abstract

Non-indigenous invasive bivalve Arcuatula senhousia was recorded in the area of the eastern Adriatic Sea in Neretva River Delta, in 2010, among tubes of well established aggregations of non-indigenous species of sedentary polychaete Ficopomatus enigmaticus at depths from 0.5 to 1 m. It was very abundant, with the maximal abundance of 102 N/400 cm2, only in very thick fouling aggregations, but any traces of colonization of this species on soft sediments were not observed. Community that inhabits aggregations of invasive polychaete was described in the paper. Occurrence of Arcuatula senhousia in wider area of very important port for international maritime transport suggests that the ballast waters could be possible vector of introduction of this species. The analysis of the sediment revealed that the species was introduced recently. In contrary, Ficopomatus enigmaticus was introduced in the area earlier.